Table 3 Genotype-phenotype correlation in index cases homozygous for SMN1 deletion
From: Spinal muscular atrophy in Venezuela: quantitative analysis of SMN1 and SMN2 genes
Family | Case | Sex | Clinical features | SMN2 copies | Onset age | SMA type |
|---|---|---|---|---|---|---|
1 | I | F | Without cephalic support, severe hypotonia, developed respiratory distress and pneumonia at 5 months of age. Died from respiratory complications at 9 months of age | 1 | < 6 months | I |
2 | I | F | Without cephalic support, severe hypotonia, progressive respiratory distress. Died from respiratory complications at 16 months of age | 2 | ||
3 | I | F | Generalized hypotonia at 6 months of age. Can stand and walk with support at 3 years old. Bilateral Babinski sign. Abolished osteotendinous reflexes, joint laxity. Decreased weight and height (P7) | 2 | > 6 months | II |
4 | I | F | Hypotonia, progressive delay in motor development. Can stand up and walk with difficulty | 2 | ||
5 | I | F | Lower limbs weakness at 8 months of age. Hypotonia, hyperlordosis, kyphosis, abolished osteotendinous reflexes, joint laxity. Decreased weight and height (P7). Can stand up with support but cannot walk at 5 years old. | 4 | ||
6 | I | F | Motor regression from 8 months of age. Lower limbs hypotonia, cannot crawl, sit, or walk at 2 years old. Abolished osteotendinous reflexes. | 4 | ||
7 | I (III-7)a | M | Severe hypotonia, inability to get up or walk without support, fine tremor of tongue, hands, and feet. | 1 | ||
7 | II (III-8)a | M | Hypotonia, affectation, and gradual weakness in proximal and distal muscles, EMG and muscle biopsy compatible with SMA | 2 | ||
7 | III (III-3)a | M | Hypotonia, affectation, and gradual weakness in proximal and distal muscles, EMG and muscle biopsy compatible with SMA | 3 | ||
8 | I | F | Generalized hypotonia, muscle hypotrophy. At 3 months, she had head support, currently she cannot sit or stand without support. | 2 | ||
9 | I | M | Generalized hypotonia. Unable to stand or walk without support. No cephalic support. EMG compatible with SMA. | 2 | ||
10 | I | F | Hypotonia. Cephalic support. Decreased muscle strength. Muscle atrophy in lower limbs. EMG compatible with SMA. | 4 | ||
10 | II (A.F.) | - | - | 3 | ||
11 | I | F | Unable to stand or walk without support. She had cephalic support. Generalized muscular spasticity, muscle weakness, tongue fasciculations. EMG compatible with AME | 3 | - |